About the power generation confirmation of the induction machine load and the influence on the islanding detection device

Abstract

The photovoltaic generation system must have protection device and islanding detection devices to connect with utility line of the electric power company. It is regulated in the technological requirement Japanese guideline and the electric equipment technology standard that the country provides. The islanding detection device detected purpose install for blackout due to the accident occurrence of the earth fault and the short-circuit in the utility line. When the islanding detection device detects the power blackout, it is necessary to stop the photovoltaic generation system immediately. If the photovoltaic generation system is not immediately stopped that electricity comes to charge the utility power line very at risk. We had already known that the islanding detection device can't detect the islanding phenomenon, if is there the induction machine load in the loads. Authors decided to investigate the influence that the inducement machine load gave to the islanding detection device. The result was confirmed the induction machine load had changed from the state of the electric motor into the state of the generator. And, the induction machine load that had entered the state of the generator changed into the electric motor driven at a synchronous speed and maintained the frequency. It was clarified not to be able to detect the islanding phenomenon because the frequency was maintained by the influence of the inducement machine load driven at a synchronous speed. The induction machine load was not able to be substituted by linear loads of an inductivity load and a capacitive load, etc. and was able to be confirmed from these results at the same time.